Headsets commonly have a headband of spring material which passes over the head of the user and is attached to the earcups. The headband is used to provide tension on the earcups to hold them against the user's head with some predetermined force and also to provide vertical support to keep the earcups from falling under the influence of gravity. The tension supplied by the headband is in the form of a bending moment transmitted along the band. If the material, stress, and moment are fixed, the only variables which remain to finish the design are the width and thickness of the band. These are covered by the equation: EQU Stress=Mc/I (1)
where M is the bending moment, c is one-half the material thickness, and I is the moment of inertia for the band cross section. For a rectangular cross section, the moment of inertia is given as: EQU I=b*h.sup.3 /12 (2)
where b is the width of the material and h is the thickness. Manipulating these equations shows that: EQU Stress=6*M/(b*h.sup.2) (3)
This last equation shows that to minimize the stress, the width b, and the thickness, h, must be made as large as practical. Since the thickness is squared in the above equation, changing the thickness will have a greater effect on the amount of stress than changing the width. The thickness and/or width must be maintained at certain levels to minimize the stress. The thickness also affects the rest radius.
Decreasing the thickness reduces the rest radius. The smaller the rest radius, the greater the distance the ends of the band must be moved before the use radius is reached. For a given use radius a smaller rest radius is desirable because a lower spring rate can be obtained. The thickness, h, however cannot be changed significantly without either affecting the rest radius or stress adversely. Decreasing the thickness to obtain a smaller rest radius will increase the stress level.
A typical prior art approach obtains a smaller rest radius and a desirable stress level by decreasing the thickness and increasing the width, b. The width that the typical prior art approach would like to use is often so large that it is beyond practical and styling limits.